CRED: Wrap task credential accesses in the HFSplus filesystem

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: James Morris <jmorris@namei.org>

fs/hfsplus/inode.c

@@ -296,8 +296,8 @@ struct inode *hfsplus_new_inode(struct super_block *sb, int mode)
 
 	inode->i_ino = HFSPLUS_SB(sb).next_cnid++;
 	inode->i_mode = mode;
-	inode->i_uid = current->fsuid;
-	inode->i_gid = current->fsgid;
+	inode->i_uid = current_fsuid();
+	inode->i_gid = current_fsgid();
 	inode->i_nlink = 1;
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 	INIT_LIST_HEAD(&HFSPLUS_I(inode).open_dir_list);

fs/hfsplus/options.c

@@ -49,8 +49,8 @@ void hfsplus_fill_defaults(struct hfsplus_sb_info *opts)
 	opts->creator = HFSPLUS_DEF_CR_TYPE;
 	opts->type = HFSPLUS_DEF_CR_TYPE;
 	opts->umask = current->fs->umask;
-	opts->uid = current->uid;
-	opts->gid = current->gid;
+	opts->uid = current_uid();
+	opts->gid = current_gid();
 	opts->part = -1;
 	opts->session = -1;
 }